Chain grate for furnaces using mechanical stokers.



A.. L. F. LEFEVRE.

CHAIN GRATE FOR FURNACES USING MECHANICAL STOKERS.

APPLICATION FILED JULY 8. I915.

1 ,26 1 ,564. Patented Apr. 2, 1918.

2 SHEETS-SHEET I- A. L. F LEFEVRE. CHAIN GRATE FOR FURNACES USING MECHANICAL STOKERS.

APPLICATION FILED JULY 8. 1915.

Patented Apr. 2, 1918.

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TATE PATENT @FFltfiE.

ARMANI) LEON FREDERIC LEFEVRE, 0F ST.-DEl-IIS, FRANCE, ASSIGNOR TO SOCIETE ANONYME DES ANGIENS ETABLISSEMENTS HOTCHKISS & CIE, 0F ST.-I)ENIS, SEINE,

FRANCE.

CHAIN GRATE FOR FURNACES USING MECHANICAL STOKERS.

Application filed July 8, 1915.

To all "whom it may concern:

. Be it known that I, ARMAND LEON FRED- nnro Lnrnvnn, a citizen of the Republic of France, residing at 5 Rue du Jambon, St.- Denis, Seine, France, have invented new and useful Improvements in Chain Grates tion considered in connection with the accompanying drawings, wherein Figure 1 is a diagram of a chain grate furnace, embodying, for example, the features of the Klepke furnace described in U. S. Patent No. 996,095.

Fig. 2 is a detail view on a larger scale showing, partly in side elevation and partly in section, a portion of a chain grate in which the features of the present invention are incorporated.

Fig. 3 is a detail end View of an alternative construction of grate bar support.

In order that the invention may be thoroughly understood, let us explain the mannor in which this kind of furnace, of which Fig. 1 is a diagrammatic View, is arranged. Broadly speaking, the arrangement consists essentially of an endless grate a on to which the fuel is fed by a distributer b; the coal burns little by little and the residues result ing from the combustion are detached from the grate by a scraper 0, above which they pass and whence they fall into the pit for the clinker. The principal role played by the scraper is, however, to stop the passage of the air which otherwise would pass directly to the chimney without passing through the layer of fuel. When the chain passes around the driving wheel (Z, the grate-bar supports leave between them much larger openings than those which separate them when they are on the two horizontal portions of the chain. The air would therefore tend to pass through these openings instead of passing through the fuel. The scraper serves at the same time to separate the grate-chamber from the chimney.

Now, it would be preferable to do away with the scraper, which it is true, does de- Patented Apr. 2, 1918.

Serial No. 38.707.

tach the clinker from the grate and passes it on to the ash-pit, but is liable to the drawback that it gives rise to an accui'nulation of clinker which gradually forms a crust, the surface of which constantly increases and to the same ext a; 1; diminishes the. active surface of the grate.

The object aimed at by the present invention is to dispense with the scraper and corn sequently to obviate the above drawback.

In order to obtain this result, the invention consists in means which prevent the formation of large openings between the gratebar supports 0 when they pass around the driving wheel (Z.

its in the known constructions, the gratebar supports a are mounted on chains a and support the usual bars f, but they also comprise rigid transverse extensions g, which, in a straight length of the chains project inward beyond the horizontal plane wherein lie the pivots of the chain links and are arranged in such a manner that the extension 1 of one of the supports is adjacent to the extension of the next support. The extensions g, g have their adjoining faces specially formed to coaot, mutually and automatically, in all relative positions of the supports 0, in establishing a joint between the adjoining supports which is substantially closed against the passage of air. Consequently, and as shown in the drawings, whatever the angular position of the supports 0 as they rotate around the driving wheel, the openings between them remain practically invariable. The prolongations g, can be attached to the supports or can be cast in one piece with them. In the same way instead of being symmetrical, as shown in Fig. 2, they may be unsymmetrical as shown by way of example in Fig. 3, the effect remaining the same.

In order to prevent the direct passage of the air situate beneath the grate into the chimney, a screen of a special type is provided and is shown by way of example in Fig. 2. This screen, which is located beneath the lower run or half of the grate consists essentially of a transverse wall 71. of refractory material, carrying a transverse flexible sheet '5, which forms a joint against the first transverse supporting roller 7' of the lower half of the chain. The wall 72., which serves to protect the sheet '5 and the roller j from the effects of the high temperature of the clinker thrown down by the bars 7*, can be inclined as shown in the drawing.

It is obvious that the joint assured by the extension 9, g at the rear end of the grate as shown in Fig. 2 is likewise secured at the front end.

I claim:

1. In chain grate for mechanical stokers, the combination with a chain, of grate bar supports fixed to said chain, said supports having; rigid transverse extensions, which in straight lengths of the chain proinward beyond the horizontal planes n nerein lie the pivots of the chain. links, the adja it extensions of adjacent supports betiornied to ee-act, mutuall and automatically, in all positions of said supports in establishing a joint between them which is substantially closed against the passage of air,

2. In a chain-grate for mechanical stokers, the combination, with a chain, of a roller said roller, Wall and sheet being located transversely of said chain beneath its lower run,

3. In a furnace using a mechanical stoker, the combination with a chain grate of a transverse support for said grate adjoining its lower run, a transverse flexible sheet making a joint With said support and a transverse Wall of refractory material so located under said grate to protect said support and said sheet against heat, as and tor the purpose set forth.

ARMAND LEON FREDERIC LEFEVRE.

Viitnesses R. H. BRANDON, LOUIS RINNY.

Copies of this atent me he obtained for five cents each by addressin the Commissioner of Eatents,

Washington, D. 43. 

